1. Field of the Invention
This invention relates to a system of multimedia multicast/broadcast service (hereinafter referred to as MBMS), especially relates to a method for initiating uplink signaling proactively by a MBMS UE.
2. Description of the Related Art
MBMS is a new service proposed by 3rd Generation Partnership Project (referred to as 3GPP) and under standardization. The MBMS is a service that transfers the same multimedia data to multiple UE Equipments (hereinafter referred to UE). In order to provide the MBMS, the system transfers the data that are originally transferred to a UE individually to multiple UEs simultaneously, which aims to make use of resources efficiently.
Firstly, the network executes the announcement of MBMS contents needed by the transmission to the UEs. After receiving this information, the UEs that determine to use this service can transfer their information to the network via a joining process. Before data transmission is started, the network sends an indication information to the UE and counts the number of UEs, which is used to decide to use point-to-point or point-to-multipoint channel type, and then the data transmission is started.
According to the connection state of radio resource control (hereinafter referred to as RRC) between the UE and a radio network controller (hereinafter referred to as RNC), states of the UE can be classified into five states, i.e. IDLE, CELL_DCH; CELL_FACH, CELL_PCH and URA_PCH and the latter four states are also called connection mode. The UE can receive MBMS data in the IDLE mode or in connection mode.
When the UE in URA_PCH mode moves to a new cell and if the cell is a new URA, the UE needs to sends an uplink message of “URA Update”. When the UE in URA_PCH mode has uplink data to transfer, or receives a paging message from the RNC, the UE needs to send an uplink message of “Cell Update”.
When the UE in IDLE mode receives a paging message or wants to initiate a service, it sends an uplink message of “RRC Connection”.
In current “RRC connection” message, 12 bits are used to indicate the reason for RRC connection establishment in which there are 20 reasons together. In current “Cell Update” message, there are 6 reasons for the initiation of the Cell Update message.
However, several reasons for the RRC connection establishment and cell update cannot meet with the requirement of the MBMS presently.
When the UE is in URA_PCH or When IDLE mode is receiving MBMS data or when Controlling RNC (CRNC) needs to collect the counting of the number of UEs, the UE in URA_PCH or IDLE mode should send an uplink message to let the RNC count the number. When the Controlling RNC needs to establish a point-to-point MBMS channel, the UE in URA_PCH or IDLE mode should send an uplink message to establish point-to-point (hereinafter referred to as PtP) channel and enter CELL_DCH state. When the UE moves to a new cell, if the UE can obtain MBMS channel configuration parameters of the new cell in advance and the MBMS channel type of the new cell is point-to-multipoint, the UE can keep staying in its original state and continue to receive the MBMS data only if re-configuring its MBMS receiving channel according to the MBMS channel configuration parameters of the new cell. However, if the channel type of the new cell is point-to-point, or the UE didn't obtain the MBMS channel configuration parameters of the new cell before the UE moves, how can the UE in URA_PCH mode obtain the MBMS channel configuration parameters of the new cell? This is an open issue in current system.